U.S. Pat. No. 4,298,025, which is owned by the present assignee, discloses a control valve for use in water softeners having two resin tanks. One of the resin tanks is normally on-line while the other tank is regenerated and placed in a standby condition until the first tank requires regeneration. The disclosed control valve controls which of the tanks is on-line and controls the regeneration sequence of an exhausted tank. The quantity of water treated by a given tank is monitored by a mechanism that includes a water usage turbine driven by water as it leaves the on-line resin tank. When a determined quantity of water is treated, which produces to a predetermined number of revolutions in the turbine, a regeneration sequence is initiated which places the standby tank on-line and isolates the exhausted tank.
A second turbine, operatively connected to a regeneration sequence control element (in the form of a disk) is rotated by a stream of water that is activated at the beginning of the regeneration cycle. The stream of water physically drives the regeneration control disk (via the turbine and associated drive train) through its sequence. As described above, the frequency of regeneration of the water softener system is determined by the usage turbine which directly measures the quantity of fluid treated by a given tank.
In U.S. Pat. No. 4,427,549 which is also owned by the present assignee, a deionization method and apparatus is disclosed. The disclosed apparatus includes a control valve similar to the control valve disclosed in U.S. Pat. No. 4,298,025 in that it includes a usage turbine for monitoring the amount of source water treated by a given tank and a regeneration control turbine for driving a control element through a regeneration sequence.
The control valves disclosed in U.S. Pat. Nos. 4,298,025 and 4,427,549 are examples of Non-Electric, Meter Driven, Demand Initiated Regenerating (DIR) fluid treating control valves. In both cases they have been designed to operate in a “Twin Tank” configuration. That is, one media vessel in Service, and one media tank in Standby mode. These units by virtue of the design features built into the control valve have enabled them to possess operational benefits unlike similar products currently in the Market. Examples include: an uninterrupted supply of treated water, counter-current regeneration, high efficiency by metered usage of the water, and regeneration with treated water to name a few.
These features, while often desirable, do come with a price. The complexity of the valve in terms of moving parts and synchronization, ability to reconfigure for changes in water chemistry, serviceability, footprint, and cost all have contributed to less than universal acceptance. It is therefore recognized that a control valve with far less complexity and increased serviceability, while still retaining key beneficial elements is needed.